Enhanced Oil Recovery by Hydrophilic Silica Nanofluid: Experimental Evaluation of the Impact of Parameters and Mechanisms on Recovery Potential

Abstract

Nanofluids as an EOR technique are reported to enhance oil recoveries. Among all the nanomaterial silica with promising lab results, economic and environmental acceptability are an ideal material for future applications. Despite the potential to enhance recoveries, understanding the two-fold impact of parameters such as concentration, salinity, stability, injection rate, and irreproducibility of results has arisen ambiguities that have delayed field applications. This integrated study is conducted to ascertain two-fold impacts of concentration and salinity on recovery and stability and evaluates corresponding changes in the recovery mechanism with variance in the parameters. Initially, silica nanofluids’ recovery potential was evaluated by tertiary flooding at different concentrations (0.02, 0.05, 0.07, 0.1) wt. % at 20,000 ppm salinity. The optimum concentration of 0.05 wt. % with the highest potential in terms of recovery, wettability change, and IFT reduction was selected. Then nano-flooding was carried out at higher salinities at a nanomaterial concentration of 0.05 wt. %. For the mechanism’s evaluation, the contact angle, IFT and porosity reduction, along with differential profile changes were analyzed. The recovery potential was found at its highest for 0.05 wt. %, which reduced when concentrations were further increased as the recovery mechanisms changed and compromised stability. Whereas salinity also had a two-fold impact with salinity at 30,000 ppm resulting in lower recovery, higher salinity destabilized the solution but enhanced recoveries by enhancing macroscopic mechanisms of pore throat plugging.

Nanoparticles in Chemical EOR: A Review on Flooding Tests

“…Recently, an attempt has been made to clarify the influence of nanoparticle concentration and salinity on oil recovery [ 24 ]. Studies were carried out with SiO 2 (12 nm) concentrations of 0.02, 0.05, 0.07 and 0.1 wt% and different salinities.…”

Effect of Temperature and Alkali Solution to Activate Diethyl Carbonate for Improving Rheological Properties of Modified Hydroxyethyl Methyl Cellulose

“…Cellulose ethers are soluble in water and possess a combination of biodegradability, nontoxicity, and renewable sourcing, making them environmentally friendly choices for various applications. , Cellulose ethers act as thickeners, texture modifiers, emulsion and suspension stabilizers, binders, adhesives, film formers, protective colloids, and structuring agents. , Due to their unique and versatile rheological properties, cellulose ethers find applications in various industries such as food, pharmaceuticals, construction, painting, and particularly the oil and gas sector. − Hydroxyethyl cellulose (HEC), hydroxyethyl methyl cellulose (HEMC), methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), and carboxymethyl cellulose (CMC) are the widely used classes of cellulose ether to be used in petroleum industry applications encompassing drilling fluid, cementing, and polymer flooding for enhanced oil recovery (EOR). , These cellulose ethers serve as viscosifying agents that enhance viscosity, prevent fluid loss, mitigate gas migration, and improve the fluid’s ability to suspend particles during drilling and cementing operations, , where the polymer is added in designed drilling mud and cement slurry to improve the flowability and properties of fluid. However, in polymer flooding for EOR applications, cellulose ethers improve sweep efficiency and mobility, ultimately enhancing oil recovery . In all these operations, the fluids are displaced from the surface to the wellbore and reservoir, requiring a high shear rate for displacement .…”

“…The mechanical shear rate, along with high reservoir temperature and salinity, affects the rheology in terms of viscosity of polymers. As the flow behavior of the displacing fluid plays a vital role in drilling and flooding operation, it becomes imperative to regulate the viscosity of cellulose ethers under specific salinity and temperature conditions, especially with high shear rates. ,− …”

“…However, in polymer flooding for EOR applications, cellulose ethers improve sweep efficiency and mobility, ultimately enhancing oil recovery. 12 In all these operations, the fluids are displaced from the surface to the wellbore and reservoir, requiring a high shear rate for displacement. 13 Furthermore, these fluids encounter formation fluid and an elevated thermal reservoir temperature.…”

“…As the flow behavior of the displacing fluid plays a vital role in drilling and flooding operation, it becomes imperative to regulate the viscosity of cellulose ethers under specific salinity and temperature conditions, especially with high shear rates. 12 , 14 − 16 …”